


Rock My World

by DaniJayNel



Series: 100 YumiKuri Stories [76]
Category: Shingeki no Kyojin | Attack on Titan
Genre: F/F, MMA AU, Oneshot, Some fighting, request, yumikuri
Language: English
Status: Completed
Published: 2015-11-06
Updated: 2015-11-06
Packaged: 2018-04-30 07:22:40
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,428
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5155217
Author URL: https://archiveofourown.org/users/DaniJayNel/pseuds/DaniJayNel
Summary: <blockquote class="userstuff">
              <p>It's just another day running a gym for Ymir, until a small blonde approaches her as she's opening up, and demands a chance to join, to become stronger. Ymir is skeptical, but she gives it to her. And Ymir is not disappointed.</p>
            </blockquote>





	Rock My World

**Author's Note:**

> Okay so I had to google most of the actual fighting stuff. Correct me if google was wrong. I’m sorry, Fightanon, that this took so long. But I hope that you enjoy it! It was so, so much fun to write. Much longer than I expected it to be, too. If you enjoy it, please don’t feel too shy to comment ^^ they really make my day. Thank you for reading! 
> 
> Prompt: modern AU set in dingy boxing/mma gym where the one of the main ladies is the owner, and the other just shows up out of the blue one day and rocks her world with her looks and skill.

Ymir slipped her rusty key inside its equally rusty lock, and grumbled as she wiggled it harshly. The chains around the worn out doors groaned and clinked in protest, but she ignored them and continued beating the lock until it goddamn opened—it was so damn old that it took forever just to unlock the fucking thing. She was just about to open her mouth and growl when someone spoke to her right.

“Please let me join!”

Ymir didn’t pause her vicious jiggling of the key, but she did suck her growl right back down and turn her head towards the voice. It was a girl, much younger than her, with long hair at her shoulders and bright, blue eyes. Ymir laughed.

“Go away, kid,” she said. “This is a gym, not a ballet studio.” The lock still wouldn’t open. “ _Goddamn fuck,_ ” she spouted, turning red now with anger.

The girl huffed and stepped closer. “I want to join your gym,” she said, her tone biting and angry. “Don’t dismiss me until you’ve seen what I’ve got.”

Ymir snorted. “Sure thing, buttercup.” The chains continued to rattle and the lock continued to be a stubborn ass.

Ymir only vaguely noticed blonde hair rushing at her, and then she was forcefully shoved aside and small, pale hands effortlessly stabbed the key all the way in, effortlessly twisted it, and then it unlocked and the chains unfurled to the ground. “There,” she said. Those blue eyes turned to Ymir, smug. “Will you give me a chance now?”

Ymir’s eyebrow was lifted in interest, but she showed no other indication that she was. She scooped her coffee from the ground—it was already lukewarm, damnit—and then pulled the metal doors open. They screeched at her in welcome. “Just because you opened a lock?” she said incredulously.

The girl straightened and her fists balled up tightly. “Please, just give me a chance.”

Ymir sighed. Apparently this girl had been harassing her fighters, begging someone to take her on, mentor her. They had all sent her away, laughing about it afterwards. Now she had arrived at the asscrack of the morning, desperate enough to speak to Ymir herself. Ymir felt mostly irritated, but a very small part of her twinged in sympathy. This girl reminded her of herself, when she was a child, small and weak.

_“Please, Levi,” she begged, tears and rain pouring over her cheeks. “Teach me how to be strong.”_

“Fine,” Ymir decided. “Get in then.”

The girl looked like she had just won the lottery. Her face brightened and a wide smile stretched across her face, making Ymir roll her eyes, and then they were inside, the doors closed, their footsteps echoing inside the old, dingy room.

“How old is this place?” the girl asked. “I’m Historia by the way.”

Ymir stopped dead in her tracks. “As in Reiss? Historia Reiss?”

The girl—Historia—nodded as if that wasn’t the most terrifying string of words to put together. “Mm-hmm. You’ve heard about me?”

“Heard about you?” Ymir muttered, walking again. She headed straight for her office, a headache already beginning to pound at her temple. It usually took Eren and Jean’s yelling, two hours from then, to really get her head hurting. “Of course I do,” she muttered again. “Who doesn’t?” She downed her entire black coffee in one gulp and then tossed the empty cup into the bin the corner of her office. Historia clapped at the successful shot.

“So you’ll let me train here?” Historia asked, hopeful. “Teach me how to be strong?”

Ymir dumped her bag beside her desk and then dropped down into the chair. “Look, Princess. The most I can do is basic self-defence. You’re the daughter of Big Reiss, our goddamn governor. If anything happens to you, my body will wash up somewhere in Mexico.”

Historia rolled her eyes. “That man isn’t my father.”

“You sure look like him.”

“I’m his illegitimate bastard,” Historia shot back. “If anything happened to me, he would be more than happy. He would probably name you his secretary or something.”

The way she said it, with such bitterness and finality, let Ymir believe it without question. So she leaned back in the chair, clasped her fingers together and then assessed the blonde in front of her. _She’s short,_ she thought. _Very slim. Her build is too small, but she can use her size as an advantage. If she can become quick on her feet, build some muscle, like Annie, then she can be a formidable opponent._ Ymir eyed the slight definition of muscle on the girl’s bicep, impressed.

“Do you work out?” she asked.

Historia seemed confused by the question, but nodded quickly. “Yeah, and I eat healthy too.”

“How long?”

“Um, since I was a kid. My father never let us eat junk food.”

Ymir snorted. “No, how long have you been working out?”

Historia blushed. “The past year. I was mugged on my way to school last year, so I decided to get into better shape.”

“Do you think you could go up against some asshole with a knife?” Ymir barked out. This girl was tiny. If she fought back, she’d be stepped on.

“Well duh,” Historia rolled her eyes. “I’m not dumb. I know my size, and if I have the stamina to run, I can escape said asshole and hide in a small hole.”

Ymir found herself laughing. “Goddamn,” she breathed. “Okay.” She stood, rounded the table and held her hand out. “Historia Reiss, welcome to my gym.”

Historia stared at the hand for a good minute before Ymir’s sigh of irritation brought her back to reality with a start, and she hastily grabbed for it. The handshake was strong, almost painful, and Ymir grinned widely when Historia didn’t flinch.

“Great,” Ymir said more to herself. “The others will be here within the hour. Before I sign you up, I want to see exactly what you can do now, and what you can do in the future.”

“Um, how?” Historia clasped her hands together nervously, but a big grin stretched her mouth.

“You’ll fight,” Ymir answered. She dropped down into her chair again and then reached for a thick folder full of papers. “Petra Ral. She’s about your height and build. She only started here a month ago, so the fight shouldn’t be too intense. You can sit there until the fight,” Ymir pointed at the only other chair in her office. “Or you can go out there and stretch. I advise the latter.” Her eyes went back to the various tax forms and the other business nonsense that came with owning and running a gym, but her peripheral vision remained on Historia, wondering what she would do.

Historia smiled and left the office to stretch. Ymir was impressed—she definitely showed promise.

Fourty-three minutes later, the others all arrived as a loud, obnoxious group. Historia had completed a set of stretches, and had even done a few squats and push-ups. Ymir had tried to focus on the forms in front of her, but she had found herself staring at Historia more than once. The kid looked like she knew what she was doing. Her work-out could use a lot of improvement, but it was definitely impressive for a beginner.

Ymir left her office quickly just as the others all noticed Historia’s small, sweaty form. Historia stood straight, stiff, though she didn’t look as scared as Ymir thought she would. Besides Petra, all her other fighters were all pretty muscled up, and all of them were tall—besides Annie, too.

“You’re back?” Jean uttered first, bursting out into a mean, obnoxious laugh afterwards. Eren rolled his eyes beside him, but he seemed just as amused that Historia had returned yet again.

Ymir had never realized how her fighters had treated this girl. She was reminded, yet again, of when she had been small, of how many people had shooed her away. Some had even physically shoved her out of the building to get the point across.

“Guys, stop being mean!” Petra attempted, her brows creased and a frown at her lips. Jean continued laughing. Behind them, Berthold towered, but he was sweating already. He looked super nervous. If he wasn’t so large and intimidating, Ymir would have never thought he could be a fighter. But goddamn, could he use his body to ram into his opponents. Reiner, who was standing beside him—and Ymir had a suspicion that Berthold rammed into him too—chuckled and puffed his beefy chest out.

“We told you, babe,” he said, staring down at her. He sounded so condescending. “You’re too small. We’d wipe the floor with you.”

Jean found that especially funny and began to snort in between laugher. Historia was visibly reddening, though Ymir couldn’t tell if it was anger or embarrassment. Either way, she’d had enough. Before anyone could realize she was in the room, she sped forward and jabbed Jean in the throat, tripped Eren by his ankles, left Berthold alone, and then kicked Reiner in the balls. All of them collapsed, and both Petra and Historia blinked in shocked surprise.

“I never knew you assholes were such pieces of shit,” Ymir spat at them, looming with her arms crossed over her chest. She rarely needed to fight anymore, since she taught others how to, organized their fights for them. She didn’t fight anymore. But she still had her strength, her skill. And she still had pent up anger that built up every day until something like this happened. She cracked her knuckles loudly. Only for special occasions like this, did she bring out her chilling glare. “Don’t let me ever hear any of you speaking to someone like that again, or I will fucking rip your dicks out, do you understand?”

Jean stood up, teeth bared, eyes fierce and alight with anger. He lunged for Ymir, snarling, but she easily flipped him over her shoulder. Eren had apparently been trying the same thing, but he stopped himself quickly when he saw how hard Jean went down.

“Petra,” Ymir started, ignoring the others to stare intently at her second newest member. “Are you ready for a quick fight? Historia will be joining our gym. I want to see her fight to assess how much help she needs.”

Ymir noticed Historia’s eyes widen. Earlier she had meant the fight as a deciding factor for if Historia would join, but now Ymir’s mind was already made up. Ymir would turn Historia into a fighting machine, able to even kick Reiner’s ass. She promised it to herself.

“S-sure thing!” Petra swallowed, likely still shaken from Ymir’s sudden onslaught. But she smiled, flashing her dimples in the way that always made Ymir soften and grow uncomfortable. “I’ll get ready right now.” She went over to Historia, smiling at her too. “I’m Petra Ral. Are you ready?”

Historia took her hand, grinning as well, and nodded. “I am, don’t worry.”

Petra hummed in delight, and then headed over to their changing room to get out of her civilian clothes. Historia was already dressed for the occasion, so she simply followed Ymir over to the right corner of the gym, where there was a large, soft mat placed on the floor

When they stepped on the mat, Historia gently took hold of Ymir’s arm to stop her. “Thank you for that,” she said softly. “Really.”

Ymir felt her heart shoot up into her throat. Up until then, this girl had been a nuisance to her as well. She had been young and naïve, but now Ymir felt something like protectiveness bubbling inside her chest. She saw herself in Historia’s sad blue eyes. No one as beautiful as Historia should have ever suffered such sadness. It made Ymir angrier than she wanted to admit.

Ymir covered Historia’s hand with her own and smiled down at her—she rarely ever smiled, either. “Look, those idiots are my idiots, and I don’t tolerate them treating anyone badly. I never taught them that.” She rolled her eyes. “I need to raise them better, so,” she grinned, reached out and tapped Historia on the nose. “You better impress them, Princess. I can only kick their balls for so long.”

Historia laughed, and then Petra joined them and the others did as well. They were slightly injured, but otherwise okay. They seemed just as eager to see this fight, so none of them tried to speak to either Historia or Ymir again. Ymir leaned against the wall to one side, watching, while the others occupied the opposite side. The whispered quietly to themselves, and Jean giggled once or twice. Ymir ignored them.

The fight began.

Petra reached out with a gloved hand, and she smiled when Historia did so and they bumped fists. “Good luck,” Petra told her.

“You too,” Historia said back. “But I’m going to kick your ass.”

Petra laughed. They were circling each other now, feet careful. Ymir studied Historia’s footwork carefully, surprised at how confident every step was, how calculated. Her body as well—she was suddenly tense, like a spring, lithe and smooth. Each movement she made was precise, thought out. Petra was much, much sloppier in her steps and movements. She projected every thought, whereas Historia was like a blank page. Ymir, of course, could tell that Historia would start out with a tentative punch, to lull Petra into thinking she really was nothing but an amateur.

Ymir bit into her lip when Historia did just that.

Petra gasped lightly as she dodged the swipe, clearly not having expected it. Ymir made a note to work on Petra’s ability to reach her opponent.

They circled each other some more, and finally the guys started to make some noise, cheering only Petra on. The door to the gym opened noisily, and only Historia didn’t take notice. Petra flicked her eyes to the people entering, and Historia took that opportunity. Ymir saw it before it even happened. Historia relaxed her body, took one silent step forward, and then struck out with an uppercut. Petra saw the strike too late, and it clipped her harshly on the jaw. She immediately tumbled to the floor. The guys were stunned silent.

Historia dropped down as well, and the grappling began. This would be a little more challenging. Petra may have been terrible on her feet, but she excelled in grappling and submission moves. Historia went for a gogoplata off the bat—which honestly, surprised Ymir. It wasn’t that common a move, so she hadn’t expected it from someone like Historia.

In the guard position, Historia caught Petra’s right arm underneath her knee, locked it there between her upper thigh and calf, and positioned the length of her leg underneath her chin, and then she pulled Petra’s head down until her throat was pressed to her shin, effectively choking her.

Ymir had been concerned for Historia when they first went down, but no one had expected this move—it required impressive flexibility. Seemed Historia had just that. Her small body shook with the force of her hold, and Petra’s valiant attempts to pull away. Sweat already coated their skin, which usually made it difficult to keep limbs from slipping away, but Historia had such a firm grip on Petra’s head and arm that it seemed she just couldn’t get out.

Petra tapped out. Historia quickly unfolded from her body, and the two collapsed in exhaustion.

“Holy shit,” Jean breathed from across the mat.

“Did that just happen?” Reiner sputtered.

“Guys, I can’t even do that move yet,” Eren whined quietly.

Ymir smirked at them, and then she approached the two figures sprawled out on the ground. “Petra,” Ymir started, grinning. “That was an impressive attempt on the playground. Your footing needs work. I’ll have Nanaba train you harder.” She ignored the way Petra immediately brightened when she should have been ashamed—she had the biggest crush on Nanaba. “And Historia,” she reached out and pulled the girl onto her feet. “I have never seen that move outside of a professional ring before.” She took a deep breath, furrowed her brows. “Don’t use it again, okay? It’s dangerous.” Historia seemed taken aback, her smile from a second ago gone, and she opened her mouth to argue. “But,” Ymir stopped her. “That was fucking amazing. You were right. You’ve definitely got something.” She grinned widely and held out a hand. “Welcome, officially, to my gym.”

Historia sucked in a few breaths. She laughed. “Thank you.” She took Ymir’s hand, but didn’t shake it, she only held onto it. “Thank you, really.” Tears welled at her eyes, and all the sadness and frustration she must have been holding back spilt out.

“Alright, back to work, idiots,” Ymir barked at the others who were all gawking. Reiner looked a little frightened now. “When I come out here again I better see lots of sweat.” She effortlessly picked Historia up—the girl was sobbing quietly now—and carried her back to her office.

Nanaba, Annie and Mikasa had entered during the fight, and they sent impressed, pleased looks towards the bundle in Ymir’s arms. Ymir sent them a cheeky grin, a nod that promised she would speak to them later, and then inclined her head towards the others, saying they should get to working out. They obeyed.

Ymir kicked her office door shut and then set Historia down on the extra chair. “I’m sorry for giving you shit before giving you a shot,” Ymir told her gently. She wiped the tears from Historia’s cheeks. “You’ve been trying for a while, haven’t you?”

Historia nodded. Tears still poured down her cheeks. “I’ve been trying so hard just to be recognized. All my life people look at me and dismiss me. Every gym I’ve been to laughed in my face. You’re the first that ever gave me a chance.”

Ymir sat down, legs crossed, and just held onto Historia, comforting her. “Well, you proved yourself.” She smiled. “And I’m going to turn you into such a goddamn fierce fighter that even Berthold will go down in ten seconds in a fight against you.”

Historia sniffled. “Is he the really tall one?”

Ymir nodded, laughing. “He gets intimidated super easily.”

“I noticed.” Historia laughed as well, and then she blushed. “I’m so sorry for crying like a baby.”

“Nah, it’s okay. I hit people to get it out, you cry. We all have our ways.”

Historia finally stopped her tears, and she eyed Ymir as she wiped them all away. “Why are you suddenly being so nice to me?”

Ymir snorted. “Me? Nice? Never.”

“Yes you are. You’re totally being a charming instructor right now.”

Ymir lifted a brow. “Are you asking me to turn into a dictator?”

“Please no.” Historia laughed even harder. “You just… you’re so tall, and dark, and scarily good looking and here you are, being so sweet to me. Why?”

Ymir shrugged. “You remind me of myself when I was younger. I also had to prove myself, you know. And besides,” she grinned. “You’re adorable.”

Historia blushed. “Are you hitting on me?”

“Only if that’s cool with you,” Ymir answered cautiously. Her eyes still shone with amusement.

Historia’s expression turned mischievous. “Will you stay late with me tonight?” she breathed, leaning forward, a hand coming to rest on Ymir’s cheek. “Train me a little longer?”

Ymir’s mind went south, and she imagined rolling on the floor with Historia, their sweaty limbs locked together, mouths panting, and breaths too harsh. She swallowed. “S-sure.”

Historia chuckled and sat back. “At least this time I didn’t need to seduce first.”

“Go out with me,” Ymir blurted. She blushed. “I mean, um, after we train tonight, would you like to have dinner with me?”

Historia grinned, pleased. “I’d love that. But I won’t unless you beat me in a one-on-one match.”

At that Ymir burst out laughing. She collapsed onto her back, convulsing. “Alright short-stuff, pick out your dress already. The winner is already decided.”

Historia watched her laugh. Ymir could tell that Historia wasn’t dumb, and she wasn’t conceited. She knew who Ymir was, no doubt. That Ymir had started out super young, had won countless fights. As good as she was, there was no way she could beat Ymir so early on.

“I’ll still try,” Historia told her, determined.

Ymir stilled, and the two shared a long, meaningful glance. “Good,” she said. “You do that.”

Historia did, but she lost the match. In the end, though, she won much more.


End file.
